M 5OT0M 




Price 25 Cents 



WINSTED SILK CO 

CHICAGO, ILL. 

Manufacturers of 

Potter's Pure Dye Spool Silk 



THE SILKWORM 

Its History and Product 



Published by 

WINSTED SILK CO. 

CHICAGO, ILL. 
Copyright, 1915, by Winsted Silk Co. All rights reserved. 




THE DISCOVERY OF THE SILKWORM 



©CI.A4 0085 5 

M 12 1915 



THE SILKWORM 




HE origin of the silk industry, like many other 
things* in history, is shrouded in the mystery of 
many legends. 

The most authentic and generally believed ver- 
sion, however, is the one that ascribes its beginning 
to the child-wife of the Chinese Emperor Hoang-ti, who 
reigned more than a thousand years before Christ. 

One day in the early Spring, this little girl, while walking 
in her garden, noticed some caterpillars feeding upon the 
leaves of a mulberry tree. They interested her, and so day 
by day she would go out to watch them. 

One day she noticed that they had stopped feeding. They 
seemed restless, moving their heads from side to side, while 
from their mouths a semi-liquid, sticky substance was issuing. 
As they moved their heads, this substance lengthened out and 
hardened, taking on the appearance of a thin, soft, fairy-like 
thread. Si-ling-chi, for that, according to the story, is said to 
have been the name of the little girl, watched the caterpillars 
industriously winding the slender, silken threads about them- 
selves. 

When she again went into the garden her pets had dis- 
appeared. In their places were many small, white, fluffy balls 
half concealed here and there under the mulberry leaves. 

She secured one of these little hiding places to see where 
the caterpillars had gone. Several of the fine threads floated 
about, and pulling on one of these, Si-ling-chi was astonished 




Incubator for Hatching Silkworm Eggs 

COPYRIGHT, 1915, BY KEYSTONE VIEW CO. 



to find that though so light it would float in the air, it was 
sufficiently tough to permit quite a length of it to be unwound 
before breaking. 

She was anxious to unwind all the threads, but the gummy 
substance with which they were covered held them firmly 
together. In her search for a way to safely unwind the thread 
she hit upon a method that is in use to this very day. Si-ling- 
chi soaked the ball in warm water until the gummy substance 
was softened. Then she began to unwind one of the threads 
and was surprised and delighted to find that it lengthened out 
into a beautiful, lustrous strand several thousand feet long. 

This, in brief, is the generally accepted story of the dis- 
covery of silk. While it is only a Chinese fable, with no 
positive assurance of its truth, there is no question but that 
the silk industry began in China, that birthplace of many 
wonderful inventions which have since had a marvelous 
influence upon modern life. 

For years the Chinese carefully guarded their secret and 
made it a source of great wealth. The beautiful silk fabrics 
woven from the threads spun by the humble caterpillar, or 
silkworm, as we know it today, gained instant popularity 
wherever they went. 

The manufacture of silk fabrics spread into all parts of 
Asia, to India, Persia and Arabia, and even into Europe, but 
the cultivation of the silkworm still remained a secret with 
the Chinese. Raw silk only was exported to these countries, 
the exporting of the eggs of the silkworm being punishable 
by death. 

This condition continued until about the middle of the 
Sixth Century, A. D., when Justinian, the Byzantine Emperor, 
induced several monks to travel into China and endeavor to 
secure some of the eggs. They were successful, carrying the 
silkworm eggs out of China concealed in hollows in their staffs. 




Feeding Mulberry Leaves to the Voracious Young Silkworms 



COPYRIGHT, 19 15, BY KEYSTONE VIEW CO. 



The silkworm thrived under the care of the Greeks, and its 
culture gradually extended into Syria, Spain and Italy, where 
it spread to Naples and Northern Italy, and finally into France. 

As long ago as 1622 the silk industry was started in 
America, when James I, of England, sent a quantity of silk- 
worm eggs and mulberry trees to the Virginia planters. This 
attempt was a failure. With characteristic energy the Ameri- 
cans kept at it, but with indifferent success. 

At the present time the cultivation of silkworms is carried 
on to some extent in California. But no country will ever be 
able to compete with the far Eastern countries like China, 
Japan and India, or even France and Italy, because of the 
labor question. The high rate of wages here is prohibitive to 
the profitable raising of silkworms. In the Eastern countries, 
and the old countries of Europe, on the other hand, the people 
engaged in the silk industry are satisfied, and can live fairly 
well on an income of ten to twelve cents per day. 

The finest silk, of course, comes from the cultivated silk- 
worm, which, through centuries of care, has been developed to 
a high degree. Wild silk, however, still forms an important 
part of the raw silk of commerce. The eggs are laid prin- 
cipally by the Tussah Moth, and the natives of China, Man- 
churia, Siam, India and other Eastern countries make a 
business of searching for the cocoons. 

There are other species which produce silk cocoons, but 
these cannot be unwound. They are used to make what is 
called spun silk, a process which we will speak of later on. 

The life of the silkworm forms one of the most marvelous 
cycles of life found in nature. It really exists in four states— 
the egg, the larva, the chrysalis and the adult, or moth. This 
entire cycle of life is not much more than two months. 

The eggs — or "seed," as the breeders call them — are 
deposited by a moth known under the scientific names of 




Chrysalis in the Cocoon 

On the left the worm is seen just entering its sleep. The view on the right shows the 

chrysalis nearly ready to emerge as a moth. Note the wings 

folded under the breast 



Sericaria mori and Bombyx mori. The latter, because the 
moth that lays silkworm eggs is of the genus of Bombycid 
moth. 

The name Sericaria was derived from the ancient land of 
Seres, or Sera, said to have been located somewhere in what 
is now Northern China, and the place where silk was first 
produced. This has also led to the term Sericulture being 
applied to the breeding of silkworms. 

In the wild state the eggs are deposited on the leaves of 
the mulberry tree during the summer, but where the worms 
are cultivated, the moths deposit the eggs on thin sheets of 
muslin, or paper. The moth does not deposit her eggs in a 
heap, but spreads them out side by side. It is not known 
positively why this is done, but probably because if placed 
one upon the other the little worms would have difficulty in 
escaping. It is certainly wonderful how instinct guides these 
little creatures, especially the worm in the spinning of its 
cocoon. 

About 350 is the usual number of eggs deposited. These 
eggs, of course, are very minute — hardly as large as the head 
of a pin — round, but slightly flattened, and dull yellow in color. 
Later they change to gray, growing lighter as the time for hatch- 
ing approaches. After the exit of the worm the shell is white. 

The eggs are collected and allowed to hatch in the Spring, 
when the mulberry trees come into leaf. Many breeders have 
three hatchings. The first, or Spring breeding, just after the 
mulberry trees begin to bud; the Summer breeding, which comes 
just after the Spring worms have spun their cocoons, and the 
Autumn breeding. Artificial hatching is carried out by placing 
the eggs in incubators or rooms heated to about 80 degrees. It 
takes from ten days to two weeks for the little worms to appear. 

The larva, or worm, when hatched is very tiny — not a 
quarter of an inch in length. It gnaws a hole in the shell, and 




Moths Emerging from the Cocoon 
This destroys the cocoon for reelirig purposes. It can only be used for manufacturing 

spun silk 



10 



after emerging grows rapidly, maturing in about a month 
(seldom over forty days). When full grown it measures about 
3^ inches in length and }i inch in thickness. 

While the silkworm has been called a hairless caterpillar, 
it really is covered at the beginning of its life with long, stiff 
hairs. It is black or gray in color, but different shades will 
come from the same batch of eggs. After the first moult, and 
as the worm increases in size, the hairs become less noticeable, 
and the worm gradually gets lighter, becoming in the last stage, 
a cream-white color. At no time during its life does it become 
entirely hairless. A microscopic examination will show 
minute hairs all over its body. 

In comparison with the other parts of its body, the silk- 
worm's head is very large. It has a large mouth with power- 
ful jaws for feeding. The body is divided into a dozen seg- 
ments, the last one having a horn-like projection rising about 
it. It has six forelegs and ten legs on the hind parts of the 
body. All the legs are provided with hooks. 

The organs with which the silkworm produces its silk 
consist of two large glands which extend along each side of 
the body for almost its entire length. These end in two 
openings in the lower jaw, which are called spinnerets. Each 
of the two openings have two apertures. The fluid issues 
from these apertures, and upon being exposed to the air 
hardens and unites into a single thread from four to seven 
times finer than a human hair. 

From birth the worm is fed upon finely chopped mulberry 
leaves. The trees must be in a healthy state to secure the 
best results, and it is said that the leaves from the white 
mulberry tree are the best for the purpose. 

It is a most curious thing to listen to many silkworms 
eating at the same time. The sound is not unlike that of the 
soft pattering of a gentle summer rain. 




Fully Developed Moths Ready to Lay Their Eggs 

The eggs are laid three or four days after emerging from the cocoon and then 

the moth dies 



During its growth the silkworm passes through several 
moults, or sicknesses, the time between these being commonly 
called "ages." There are, under normal conditions, four 
moults, and five ages; the last of the ages is the one just 
before the worm goes into the cocoon, or chrysalis form. 

During the moults the worm ceases to eat, and sheds its 
skin, which apparently does not grow as fast as the worm. 
When ready to moult the skin splits in front and the worm 
wriggles the skin off at the back without moving from the one 
spot. The time between these moults is about as follows : 

First period, five to six days; second, four to five; third, 
about five; fourth, five to six; and the fifth, or last, eight to 
ten. The worm spends about nine days of its month or so 
of growth in fasting. 

At other times, however, the silkworm is a voracious 
eater. It has been estimated that a worm consumes its own 
weight of leaves every day that it feeds. During the last few 
days, just before beginning its work of spinning, it eats more 
than during its whole previous existence. 

When the worm is full grown and ready to spin its 
cocoon it stops eating and becomes very restless, moving its 
head about and wandering in search of a suitable place to 
begin its spinning. The cultivated silkworm at this time 
generally shows a desire to climb. In the wild state the silk- 
worm usually fastens or sews two mulberry leaves together 
and spins its cocoon between them. 

Breeders of silkworms watch for this stage in its devel- 
opment, and at the proper time arrange some material like 
branches or straw over and around the worms. The worms 
climb into this and begin their spinning. 

When spinning, the worm attaches itself by means of its 
five pairs of back legs, leaving the front of the body and head 
free to move about. It fastens a thread, and then moving its 




A Section of the Mammoth -Plant of Mitsui Company at Maebashi, Japan 
Boiling the Cocoons and Reeling Silk 



COPYRIGHT, 19 16, BY KEYSTONE VIEW CO 



head from side to side gradually begins the construction of the 
cocoon about itself. The threads are wound loosely at first, 
forming a shell, but as the worm encloses its body by building 
toward itself they become more regular and closely set. The 
worm, however, does not spin all the threads round and round 
its body. Yards and yards of a cocoon can be unreeled without 
the cocoon turning over. 

It has been estimated that a silkworm makes about sixty- 
five motions with its head every minute, and in that time about 
four to six inches of the filament flow from the spinneret. The 
gummy substance, which, by the way, forms a large proportion 
of the thread or filament, causes the filaments to adhere closely 
and when completed the cocoon forms a solid mass. 

The time of spinning a cocoon takes all the way from two 
to five days, but the latter number is the usual average. 

Cocoons are white, yellow and green, but the green do not 
make as fine a quality of silk, and are harder to bleach. They 
vary in size and form, but the usual shape is oval, somewhat 
resembling a peanut. The size averages 1 to V/?. inches in 
length and from % inch to 1 inch in thickness. 

About three days after the cocoon is completed the worm 
passes into the chrysalis form. This is the most phenomenal 
change known in nature. The worm lies dormant or "sleeping". 
During this time it again sheds its skin, and in from fifteen to 
twenty days it awakens a new creature. All the organs of 
the body, both internal and external, undergo a complete change. 

With the shedding of the skin it loses ten of its sixteen 
legs. The mouth opening disappears, while two large compound 
eyes, four scaly wings, and two feathery antennae or "feelers" 
grow. Having no jaws with which to cut its way out, the moth 
is provided with a liquid secretion, strongly alkaline in its com- 
position. With this it moistens the threads at one end of the 
cocoon, dissolving the gummy substance, and then forces its 
way out. 




Reeling Silk from Cocoons 



COPYRIGHT, t 9 15. BY KEYSTONe VIEW CO. 



lb 



When the grayish-white moth emerges its wings are damp 
and folded under its breast. They soon dry and expand, and 
the moth, if a female, is ready to fulfill its mission. It lays its 
eggs within the next three or four days, and its usefulness being 
gone, it then dies. During its life the moth never moves more 
than six inches in any direction from the spot of its birth. 

The eggs are collected and stored in a cool place until they 
are wanted. In Japan the eggs are stored in a natural cold cave 
called Fuketsu. These are found in nearly all of the silk raising 
districts, and preserve the eggs indefinitely if necessary. 

Of course, when the moth breaks out, the cocoon is spoiled 
for reeling, and can only be used for making spun silk. For 
this reason only a few of the moths are allowed to emerge for 
breeding purposes. The balance of the cocoons are taken as 
soon as the worm has finished its work and "stoved". That is, 
the cocoons are placed in ovens to kill the chrysalis, and so 
preserve the cocoon intact. In some cases the cocoons are 
placed in boiling water for the same purpose. After the 
chrysalis is killed the cocoons can be kept for any length of 
time. 

The first step in the manufacture of silk then begins. This 
is called reeling. The reeling of raw silk is usually conducted 
as a separate business, and the places where this is done are 
called "filatures." The cocoons are bought from the breed- 
ers, the chrysalis killed, and the cocoons stored until required 
for reeling. Before reeling, the cocoons are placed in shallow 
pans of hot water to soften the gum and loosen the ends of 
the threads, or "floss," which the outside threads of the cocoon 
are called. 

Then a brush, similar to a whisk broom, is stirred in the 
water and the loose threads attach themselves to it. When the 
brush is withdrawn from the water it is possible to select the right 
filament or thread for unwinding or reeling, and this is done 

17 




\s Precious as Gold. Weighing Skeins of Raw Silk on Delicate Scales 
in Japan 

/PYRIGMT, 1915, BY KEY STON E VIEW CO. 



direct from the water. The outside threads cannot be used for 
reeling, but are not wasted, being manufactured into spun silk 

Spun silk, which has been referred to several times in this, 
story, is manufactured in a manner similar to cotton and woolen 
threads, going through the various process of washing, combing 
and spinning. 

A single cocoon strand which, by the way, runs from 2,000 
to 4,000 yards, is too fine for commercial use. Because of this 
the threads from several cocoons, usually about six or seven, 
are reeled together. As they are reeled while moist, the 
natural gum with which they are covered forms them into a 
single thread. Although the silkworm spins as much as 4,000 
yards of thread, there are seldom more than 900 yards available 
for reeling first quality silk. 

After being wound on a reel the silk is then formed into 
skeins, and becomes the raw silk of commerce. This is the 
shape in which it arrives in this country, and is purchased 
from the silk brokers by the Winsted Silk Company, to be 
manufactured into the popular sewing silk known as 
Potter's Silk. 

The next step in the manufacture of silk, after it goes 
into the manufacturers' hands in this country, is "throwing." 
This is probably derived from an old Anglo-Saxon word, 
"thrawan," which means to twist, and that is exactly what is 
done. As the several strands of the raw silk thread are only 
held together by their natural gum, they would loosen and 
become entangled in the washing and dyeing processes 
through which they go. 

A special machine is used for "throwing." On this the 
raw silk is unwound from bobbins, twisted, and wound again 
on reels. The manufacture of sewing silks like Potter's 
Pure Dye Spool Silks is simply a continuation of the 
"throwing." 

19 



After ''throwing," the silk thread is sent to the dye house, 
where it is thoroughly washed by boiling to remove the 
gummy substance with which it was originally covered, and 
then dyed in the great variety of shades that permit its being 
perfectly matched with all colors and shades of fabrics. 

A few figures may not be out of place here, and will give 
some idea of the extreme lightness of silk threads which adds 
to the difficulty of working it. The original strand as spun 
by the silkworm is so fine that 22,000 yards of it— more than 
five miles—only weigh one ounce. When several threads 
are wound together to make the usual thread of commerce, it 
takes over 180 miles of it to weigh one pound. It takes in 
the neighborhood of 3,000 cocoons to make one pound of raw 
silk. A spool of Potter's Silk, containing 100 yards of pure 
silk thread, and retailing for ten cents, requires 150 cocoons. 



WINSTED SILK CO, 



Chicago, 111. 




20 




You Should Have This 
Silk Culture Cabinet 

Here is an opportunity for everyone to study 
the life development of the wonderful little 
Silkworm. This Culture Cabinet shows 

All Stages of Silkworm Growth 

direct from Nature. The actual Moth, Eggs, Worms and Cocoons are 
here for your inspection. Cabinet is handsome and durable. Exhibits 
are carefully arranged. Considerable time and money was expended in 
gathering the material and making up these cabinets. 

Price Complete $2.50 

Schools, Colleges and Educational Institutions 

will find it a valuable addition to their courses of study. When pur- 
chased by an authorized educational official we will allow a special 
discount of 50 per cent. 

SPECIAL EDUCATIONAL 
OFFER 

In connection with this story of the silkworm it would be most instructive to have 
a real cocoon, just as spun by the silkworm in some faraway Eastern country It is 
an interesting thing, too, to have to show to your friends. 

If you will save 5 empty spools that have contained Potter's Sewing Silk, and 
return them to your dealer, we will send you a real cocoon, imported straight from the 
breeders. 1 his offer is limited to not over two cocoons to a person. Enclose 2c stamp 
•ii u n °- now to save your s P° ols - Get your Wends to save them for you. You 
will be surprised to see how quickly they accumulate. You will be more than delighted 
when you receive a real cocoon to examine, study and keep. 

If you want another copy of this book for a member of your family, or some friend 
return one empty spool that has contained Potter's Silk to your dealer, or to us, and 
we will send you another book. 

Winsted Silk Co., Chicago, 111. 




LIBRARY OF CONGRESS 

I Mill 




Potter's Pure Dye Spool Silk 

Potter's is the perfect sewing silk. Strong, smooth in 
texture and beautiful in appearance. Easy to thread 
through needle, and will not catch in goods, or knot. 

Famous for Over 40 Years 

It has stood the test of competition. Large and ever-growing sales 
of Potter's are due to the complete satisfaction which it gives users. 

Potter's Pure Dye Spool Silks gives the best results to 
the home dressmaker or the professional seamstress 

WINSTED SILK CO. 

CHICAGO, ILL. 



